Disc drives are commonly used in work stations, personal computers, portable computers, and other computer systems to store large amounts of data in a form that can be made readily available to a user. In general, a disc drive comprises one or more magnetic discs that-are rotated by spindle motor at a constant high speed. The surface of each disc is divided into a series of data tracks which are spaced radially from one another across a band having an inner diameter and an outer diameter. The data tracks extend generally circumferentially around the discs and store data in the form of magnetic flux transitions within the radial extent of the tracks on the disc surfaces. Typically, each data track is divided into a number of data sectors that store fixed sized data blocks.
A head includes an inner active element such as a magnetic transducer which senses the magnetic transitions on a selected data track to read the data stored on the track, or to transmit an electrical signal that induces magnetic transitions on the selected data track to write data to the track. The head includes a read/write gap that positions the active elements of the head at a position suitable for interaction with the magnetic transitions on the data tracks of a disc as the disc rotates.
Each head is mounted to a track accessing arm that is rotated by an actuator to selectively position the head over a pre-selected data track of the disc to either read data from or write data to the pre-selected data track. The head includes a slider assembly having an air-bearing surface that causes the head to fly over the data tracks of the disc surface due to fluid air currents caused by rotation of the disc.
Typically, several discs are stacked on top of each other and the surfaces of the stacked discs are accessed by the heads mounted on a complimentary stack of track accessing arms that are attached to the actuator to form an actuator assembly. The actuator assembly generally includes head wires which conduct electrical signals from the heads to a flex circuit, which in turn conducts the electrical signals to a printed circuit board mounted to a base of the disc drive.
Continued demands exist for higher disc drive performance from disc drives having smaller form factors. Such demands require increases in spindle motor rotation speeds, increases in a real density recording capabilities, and faster data access times, along with decreases in the size of the disc drive components and the housing that encloses them. Standard disc drives used in personal computers are formed in accordance with a one-inch form factor (height). Such standard disc drives have been essentially miniaturized to form microdrives. Such microdrives typically have a 5.0 millimeter (mm) form factor and are formed in accordance with compact flash Type II specifications. One of the difficulties in meeting such a small form factor is the formation of the base of the microdrive that provides support for the components of the disc drive.
Disc drive bases are designed to provide the necessary structural integrity to support the mounting of internal disc drive components as well as to support attachment of the disc drive to a user environment. Typically, disc drive bases are formed from a casting process using aluminum and undergo secondary machining operations as required to form the requisite critical surfaces for proper alignment of the disc drive components. While structurally solid, such cast bases have limitations. For example, the formation of a base for a 5.0-mm form factor microdrive can push the limits of the casting process as typical wall thicknesses can be as small as 0.3 mm.
To meet the continued demands for ever decreasing form factors, such as the 3.3 mm form factor of compact flash Type I specifications, requires the development of new base designs utilizing alternative manufacturing processes. Embodiments of the present invention provide solutions to meet such disc drive base demands while offering other advantages over bases of the prior art.